• Journal of Magnetics
• /
• v.16 no.3
• /
• pp.271-275
• /
• 2011

This paper proposes a magnetoelectric (ME) composite transducer structure consisting of a magnetostrictive H-type Fe-Ni fork substrate and piezoelectric PZT plates. The fork composite structure has a higher ME voltage coefficient compared to other ME composite structures due to the higher quality (Q) factor. The ME sensitivity of the fork structure reaches 12 V/Oe (i.e., 150 V/cm Oe). The fork composite with two PZT plates electrically connected in series exhibits over 5 times higher ME voltage coefficient than the output of the rectangle structure in the same size. The experiment shows the composite of a Fe-Ni fork substrate and PZT plates has a significantly enhanced ME voltage coefficient and a higher ME sensitivity relative to the prior sandwiched composite laminates. By the use of a lock-in amplifier with 10 nV resolution, this transducer can detect a weak magnetic field of less than $10^{-12}$ T. This transducer can also be designed for a magnetoelectric energy harvester due to its passive high-efficiency ME energy conversion.

• Annual Conference on Human and Language Technology
• /
• 1993.10a
• /
• pp.437-447
• /
• 1993

국제 협약에 따라 한글에 관한 정보는 로마자로 표기해야 한다. 우리나라는 1959년 2월 로마자 표기법'을 제정, 수차례 개정을 통해 1983년 6월 문교부(Ministry Of Education)안을 발표했으나, 표지판, 역명, 교과서, 공공문서들에서 활용되었지만, 영자신문, 외국 학술지등은 M-R( Mccune-Reishauer ) 표기법을, 인명, 신문 및 방송매체 등은 혼합표기방식을 사용함으로써 인(人). 지명(地名), ID, 대표어등 정보 검색시 혼란을 야기시켰고, 개정안에 따를 표기 정정으로 수백억원에 가까운 예산을 낭비하였으며, 최근 ISO(International Standard Organization)에서는 남북한 단일화 및 기계적 변환을 요구하고 있으나, 반달표 표기곤란, 편리성 결여, 북한의 주장등의 사유로 제정등을 거론하고 있는 실정에 있다. 잘 쓰지 않는 ASCII 코드 중에서 반달점 폰트를 제작하고 단어, 문장, 문서를 STRING으로 받아 알고리즘화된 음운법칙을 적용하여 소리글자로 변환하고 MOE테이블에서 대응글자를 참조하여 기계적 변환이 가능하도록 하였으며, 세련된 디자인, 풀다운 팝업방식을 채택, 2HD 1장으로 국내최초로 개발하였다.

• Journal of The Korean Association For Science Education
• /
• v.36 no.6
• /
• pp.815-833
• /
• 2016

This study investigated children's (grade 3 to 9) responses to assessment items on energy as a cross-cutting concept in order to get basic information for a learning progression. The assessment consisted of 8 ordered multiple-choice items at the contexts of electric circuit, mechanical energy of falling objects, phase change of matter, dissolution, biological phenomena of a lizard, food chain, radiative equilibrium between Sun and Earth, and the system of water cycling. Children's responses to each item were analyzed with using cross-tabulations in terms of grades and item option levels and Wright map and Differential item functioning based on Rasch modeled item response analysis. The results offered empirical evidence of children's development of understanding energy from relation between energy and its phenomena, types of energy, transfer and conversion of energy, towards conservation and equilibrium of energy for all of eight contexts. Children of each grade did not fully understand energy conservation. As grade goes up, their understandings of energy transfer and conversion were differentiated across the contexts and topics of energy. According to Rasch analysis, children had easier understanding of energy on dissolution and poorer understanding of energy on water cycling than that on other contexts. It was discussed and suggested that the results of this study help us organize science topics with regard to energy when developing new national science curriculum.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.5
• /
• pp.1433-1439
• /
• 2014

We report on the influence of water as an electrolyte on the photovoltaic performances. The photovoltaic performance was shown to be quite sensitive to the substituent on the donor group. An optimized efficiency of 4.41% in the presence of 100% water content using $I^-/I{_3}^-$ redox couple was obtained using the D21L6 organic dye.

• Carbon letters
• /
• v.14 no.1
• /
• pp.58-61
• /
• 2013

In this work, the effect of catalysts on the mechanical properties of carbon fibers-reinforced epoxy matrix composites cured by cationic latent thermal catalysts, i.e., N-benzylpyrazinium hexafluoroantimonate (BPH) was studied. Differential scanning calorimetry was executed for thermal characterization of the epoxy matrix system. Mechanical interfacial properties of the composites were studied by interlaminar shear strength (ILSS), critical stress intensity factor ($K_{IC}$), and specific fracture energy ($G_{IC}$). As a result, the conversion of neat epoxy matrix cured by BPH was higher than that of one cured by diaminodiphenyl methane (DDM). The ILSS, $K_{IC}$, $G_{IC}$, and impact strength of the composites cured by BPH were also superior to those of the composites cured by DDM. This was probably the consequence of the effect of the substituted benzene group of BPH catalyst, resulting in an increase in the cross-link density and structural stability of the composites studied.

• Journal of Fisheries and Marine Sciences Education
• /
• v.17 no.1
• /
• pp.76-85
• /
• 2005

GIS (Geographic Information Systems) technology is a necessary function to support location based on service by using GPS in the mobile environment. These mobile systems have basic functional limitations such as a low rate of processing, limited memory capacity, and small screen size. Because of these limitations, most of the mobile systems require development of a reduced digital map to overcome problems with large-volume spatial data. In this paper, we suggest using the reduced digital map format in order to use location based on service in a PDA environment. The processing of the proposed data format consists of map generation, redefinition of layers, creating polygons, and format conversion. The proposed data format reduces the data size by about 98% comparing with DXF format based on the digital map of Busan.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.262-264
• /
• 2005

We propose a filter design method to suppress the effect of gyroscope mixed random errors at INS system level. It is based on the result that mixed random errors can be represented by a single equivalent ARMA model. At first step, the time difference of equivalent ARMA process is performed, which consider the characteristic of indirect feedback Kalman filter used in INS filter. Next, a state space conversion of time differenced ARMA model is achieved. If the order of AR is greater than that of MA, the controllable or observable canonical form is used. Otherwise, we introduce the state equation of which the state variable is composed of the ARMA model output and several step ahead predicts of that. At final step, a complete form state equation is presented. The simulation results shows that the proposed method gives less transient error and better convergence compared to the conventional filter which assume the mixed random errors as white noise.

• Convergence Security Journal
• /
• v.5 no.3
• /
• pp.9-14
• /
• 2005

In this treatise when, proposed to supplement studying contents relationship conversion service and cooperation studying service function to LMS that analyze existing e-learning model's limitation for ubiquitous environment e-learning model that can study regardless of, ubiquitously, some contents and do based on SCORM ubiquitous-network and next generation sensor technology etc.

• The Journal of Korean Association of Computer Education
• /
• v.7 no.5
• /
• pp.101-110
• /
• 2004

The multimedia community needs an environmental data representation and interchange mechanism which not only satisfies the requirements of today's systems, but can be extended to meet future data sharing needs. This mechanism must allow for the standard representation of, and access to data. The SEDRIS STF(SEDRIS Transmittal Format)provides environment data users and producers with a clearly defined interchange specification. In this paper I develop data converter commercial data(3DS MAX) format to standard interchange format and vice verse without losing semantic of information content using SEDRIS standard interchange format.

• Proceedings of the IEEK Conference
• /
• 2002.07b
• /
• pp.1034-1037
• /
• 2002

A switched-capacitor(SC) type DC-DC converter having capability of integrated circuit fabrication have been marked for the application of mobile equipments. Especially, a ring type SC power supply is featured by the flexible and dynamic voltage conversion ratio change. In this paper, an improvement of the gate driving techniques is proposed for high power efficiency and less area occupation on the chip. Furthermore, its power-saving operation in the stand-by state is proposed. The three-capacitors ring type power supply is really designed and discussed. As results, the simulation results shows the high efficiency of 92.1%, and the higher output put voltage of 10.5 V compared with conventional one of 8.6 V.